<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        div.parent{
            width: 200px;
            height: 200px;
            background: red;
        }

        div.center{
            width: 150px;
            height: 150px;
            background: green;
        }

        div.children{
            width: 100px;
            height: 100px;
            background: blue;
        }
    </style>
</head>
<body>
    <!-- <div id="parent" class="parent" style="background: red;">
        <div id="center" class="center" style="background: green;">
            <div id="children" class="children" style="background: blue;">
    
            </div>
        </div>
    </div>
    <div>
        <button id="btn-addchildnode">添加子节点</button>
    </div> -->

    <div style="padding: 10px">
        <h3>属性更改</h3>
        <div id="attributes-change" data-a="111" style="width: 200px;height: 200px;background: blue;"></div>
    </div>
    <div style="padding: 10px">
        <h3>文本内容更改</h3>
        <div id="characterdata-change">
            这是文本
        </div>
    </div>
    <div style="padding: 10px">
        <h3>子节点增删更改</h3>
        <div id="childlist-change">
            <div>1</div>
            <div>2</div>
        </div>
        <button id="childlist-change-btn">添加和删除节点</button>
    </div>
</body>
<script src="./index.js"></script>
</html>